Kinds of Laser Pointer pen

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Clarence

Kinds of Laser Pointer pen

Post by Clarence »

GadgetTown.com sale Green Lasers, price start at $13.99. http://www.gadgettown.com/Green-Lasers- ... 2grid#main
GadgetTown.com sale Red Lasers, price start at $4.99. http://www.gadgettown.com/Red-Lasers--2614
GadgetTown.com sale other color Lasers, price start at $30.99. http://www.gadgettown.com/Other-Flashli ... sers--2616

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Note: Laser is harmful to people, following uses are forbidden
* A. Point the laser at people's faces, especially eyes
* B. Point at mirrors or highly reflective surface
* C. For children play
* D. Observe the laser lines with a telescope
* E. Disassemble, test or repair laser pens
dave battin

Kinds of Laser Pointer pen

Post by dave battin »

which ones are good for holography?
holo_cyware

Kinds of Laser Pointer pen

Post by holo_cyware »

Obviously none; probably the 5 mW red one would work though.

Somebody should delete this kind of crap. These sellers would post here as they find us in google with lots of laser hits.
Joe Farina

Kinds of Laser Pointer pen

Post by Joe Farina »

Well, at least this was posted in the "for sale" section. And since many of these are low-priced lasers, they can at least be used for pointers when it's discovered they won't work for holography :wink: Maybe some of the low-power red ones will work.

Actually, I can think of a good holographic use for a cheap 532nm laser that won't produce holograms (and I didn't know they could be that cheap). If someone is working on sculpture that's painted for a two-color hologram (532nm and red), and the sculpture workshop is far removed from the lab (as mine is), it would be helpful to have a small green laser (532nm) and the same type of red laser (but also lower-power) joined into a single beam (with a dichroic mirror) to serve as an illumination source when the sculpture is being painted. Then it can be checked under this illumination for correct appearance, without having to go back to the lab, fire up the main lasers, and look at it.
holo_cyware

Kinds of Laser Pointer pen

Post by holo_cyware »

It would also work well for a transmision hologram.
Clarence

Kinds of Laser Pointer pen

Post by Clarence »

Statement:

:angel: Laser Pointer on our website are sold by wholesale. Just a shopping recommendation.

Instruction:

A laser pointer is a small laser designed to highlight something of interest by projecting a small bright spot of colored light onto it. The laser beam is not in itself visible from the side, but is visible as a result of light scattered by dust particles along the beam path. The small width of the beam and low power of typical laser pointers make the beam itself invisible in a reasonably clean atmosphere, showing a point of light when striking an opaque surface. Some higher powered laser pointers are faintly visible via Rayleigh scattering when viewed from the side in moderately to dimly lit conditions.
①This is a commonly used product for meetings and conferences, let you speak out freely.
②The beauty beam light is extreme suitable use at night, which can point out the very right position of the star you are looking. A very good star-pointer.
③This is the commonly used product for demonstrations and presentations in classes, and other activities, making listeners feel release.
④Can be used in museums and all kinds of exhibitions, a very good guide for your travelling, your best Companion.
⑤Best guide for the climbers and people in mountainous areas. Good tool for pointing out the faraway target and sending out the SOS signal, making your travel more fun.
⑥This laser can measure you the accurate position of the building in the faraway distance by avoiding going close to the dangerous field. Truly an very ideal replacement for your monitoring alive.

Working Principle:

①The green light is generated in an indirect process, beginning with a high-power (typically 100-300 mW) infrared AlGaAs laser diode operating at 808 nm
②The 808 nm light pumps a crystal of neodymium-doped yttrium aluminum vanadate (Nd:YVO4) (or Nd:YAG or less common Nd:YLF), which lases deeper in the infrared at 1064 nm
③The vanadate crystal is coated on the diode side with a dielectric mirror that reflects at 808 nm and transmits at 1064 nm
④The crystal is mounted on a copper block, acting as a heat sink; its 1064 nm output is fed into a crystal of potassium titanyl phosphate (KTP), mounted on a heat sink in the laser cavity resonator
⑤The orientation of the crystals must be matched, as they are both anisotropic and the Nd:YVO4 outputs polarized light. This unit acts as a frequency doubler, and halves the wavelength to the desired 532 nm
⑥The resonant cavity is terminated by a dielectric mirror that reflects at 1064 nm and transmits at 532 nm. An infrared filter behind the mirror removes IR radiation from the output beam, and the assembly ends in a collimator lens
⑦Nd:YVO4 is replacing Nd:YAG and Nd:YLF due to lower dependency on the exact parameters of the pump diode (therefore allowing for higher tolerances), wider absorption band, lower lasing threshold, higher slope efficiency, linear polarization of output light, and single mode output
⑧For frequency doubling of higher power lasers, LBO is used instead of KTP. Newer lasers use a composite Nd:YVO4/KTP crystal instead of two discrete ones
⑨Some green lasers operate in pulse or quasi-continuous wave (QCW) mode, to reduce cooling problems and prolong battery life
BobH

Kinds of Laser Pointer pen

Post by BobH »

I think the laser pointer crowd is responsible for all the negative reputation lasers have gotten over the past few years. Ever since cheap green pointers became available. The children at laser pointer forum demonstrate this. I recently was shown a handheld green laser putting out 400mW!!!

There is NO reason to hold a laser by hand that's outputting that much power. Same with 35mW. NO reason. A handheld laser over 5mW is a directed energy weapon.

Everyone on this forum knows all about the availability of laser pointers. Selling them here should not be permitted, in my opinion. I hope this user is removed.
Joe Farina

Kinds of Laser Pointer pen

Post by Joe Farina »

I bought one of those 532nm pointers (advertised as 10mW) for $14.99 (free shipping). They shipped it very quickly.

I put the batteries in, pressed the button, and there was a bright green spot on the wall. I brought out the Lasercheck, to measure the power, and slid the cover off, for readings under 10mW. I was getting some odd readings, and the Lasercheck was beeping for some reason. Then I slid the cover back, for readings over 10mW, and got some readings around 188mW. I thought my Lasercheck was calling it quits. But nope, I checked my little 5mW HeNe, and the reading was normal.

So you can buy a new 188mW green pointer these days for 15 bucks. There is a little danger label on the pointer that says "max output power <10mW"

I have to be amazed that such things are still being sold in such a careless manner.
rzeheb

Kinds of Laser Pointer pen

Post by rzeheb »

I wonder how much of that 188 mw was really IR?
Joe Farina

Kinds of Laser Pointer pen

Post by Joe Farina »

rzeheb wrote:I wonder how much of that 188 mw was really IR?
Good question, offhand I can't think of a way to test it.
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